DE2124592B2 - Process for the manufacture of polyethylene - Google Patents

Description

(1) a small-sized, inorganic particle diameter of 0.0001 to 2 mm, Support material containing metals in chemical bond as well

(2) a Ziegler-type catalyst applied to the support material

(2.1) a catalyst component made from a chloride, oxychloride or alkoxychloride of titanium, zirconium or vanadium as well as

(22) a catalyst component of a saturated metal alkyl, saturated metal alkoxyalkyl or saturated metal alkyl halide of the metals aluminum, 2s Magnesium or zinc or a lithium alkyl,

with the provisos that the weight ratio of support material (1): catalyst component (2.1) - based on the transition metal - is in the range from 100: 0.1 to 100: 10 and the atomic ratio of transition metal of the catalyst component (2.1): metal of the catalyst component (22) in the range from 100: 1 to 100: 10000, characterized in that the catalyst system. (KS) is used in the form of an intimate mixture (GE) of the catalyst system (KS) and a small-scale, a particle diameter of 0.1 to 6.0 mm having, at the selected polymerization temperature non-softening ethylene polymer (ÄP), the particles of mixture (GE) but are coated with a solid at 30 ⁰ C, is liquid at the chosen polymerization temperature, saturated hydrocarbon wax (WA) such that the weight ratios are given as

(KS): (ÄP) from 1:10 to 1: 1000;

(KS): (WA) from 1: 0.01 to 1: 1000; as

(ÄP): (WA) from 1: 0.001 to 1: 1.

50

2. The method according to claim 1, characterized in that a catalyst system is used in which the support material (1) is a material which has been obtained by holding 1 to 100 hours at a temperature of 150 to 600 ⁰ C from a Substance of the general formula

60

(Me ") m · (Me '") ,, · (OH) ₀ ■ (CO ₃ ), · (H ₂ O),
where stand

Me "for a bivalent state

Metal or transition metal;
Me ¹ "for a trivalent state

Metal or transition metal;

m for an integer from 1 to 10;

π for an integer from 2 to 5;

ο for an integer from 2 to 24;

ρ for an integer from 1 to 3;

q for an integer from 0 to 10;

with the proviso that the relationship holds

2n + 3m = o + 2p = an integer from 8 to 26.

3. The method according to claims 1 to 2, characterized in that the to be polymerized Ethylene used in a mixture with hydrogen in such a way that to 100 volume miles of the to polymerizing ethylene eliminates up to 150 parts by volume of hydrogen.

uie invention relates to a process for producing finely divided polyethylene having a particle diameter of 0.1 to 6.0 mm by polymerization of ethylene at temperatures of 50 to 130 ⁰ C and pressures of 10 to 200 atm in a moving bed dry, finely divided polyethylene having a particle diameter of 0.1 to 6.0 mm by means of a catalyst system (KS)

(1) a small-sized, inorganic particle diameter of 0.0001 to 2 mm, Support material containing metals in chemical bond as well

(2) a Ziegler-type catalyst applied to the support material

(2.1) a catalyst component made from a chloride, oxychloride or alkoxychloride des Titans, zirconium or vanadins as well

(2.2) a catalyst component composed of a saturated metal alkyl, saturated metal alkoxyalkyl or saturated metal alkyl halide of the metals aluminum, magnesium or zinc or a lithium alkyl,

with the provisos that the weight ratio of support material (1): catalyst component (2.1) - based on the transition metal - in the range from 100: 0.1 to 100: 10 and the atomic ratio of transition metal of the catalyst component (2.1): metal of the Catalyst component (2.2) in the range from 100: 1 to 100: 10,000

Processes of this type known to you have some advantages over comparable other processes Properties; The disadvantage, however, is that the resulting small-sized polyethylene is a relatively large one Fraction of particles whose particle diameter is less than 03 mm. This is for two reasons undesirable: on the one hand, it prevents movement of the bed and thus good mixing of the Reaction mixture made considerably more difficult, and on the other hand there are funding difficulties in the Processing of the polyethylene (poor penetration into the machines).

The invention was based on the object of a method of the input! to show the defined type that is not burdened with the aforementioned disadvantage or is burdened to a much lesser extent.

It has been found that the problem can be solved if the method

Catalyst system (KS) is used in the form of a mixture (GE) of the catalyst system (KS) and one certain, small-particle ethylene polymer (ÄP), the particles of the mixture (GE) with a certain wax (WA) are coated in a certain way.

In addition, some particularly advantageous additional developments of the method were found, they will come back to later.

The invention accordingly relates to a process for the production of polyethylene by polymerizing ethylene at temperatures of 5 (1 to 130 ⁰ C and pressures of 10 to 200 atmospheres in a moving bed of dry, small-particle polyethylene with a particle diameter of 0.1 to 6, 0 mm medium :, of a catalyst system (KS)

(1) a small, one particle diameter from 0.0001 to 2, preferably from 0.0001 to 1 me having inorganic carrier material containing metals in chemical bond, as well as

(2) one applied to the carrier material Z5egler-type catalytic converter

(2.1) a catalyst component made of a chloride, oxychloride or alkoxychloride (especially Ci to Ci2 alkoxy chloride) of titanium, Zirconium or vanadins as well

(22) a catalyst component composed of a saturated metal alkyl (especially metal-d to ciralkyl), saturated metal alkoxy alkyl (especially metal-Cr to dralkoxy-d- to ciralkyl) or saturated metal alkyl halide (especially metal cibu, ciralkyl chloride) of the metals aluminum, Magnesium or zinc or a Lithium.Jkyl (especially lithium-Ci- to lkl)

with the provisos that the weight ratio of support material (1): catalyst component (Zl) - based on the transition metal - is in the range from 100: 0.1 to 100: 10, preferably from 100: 0.3 to 100: 5, and the atom The transition metal ratio of the catalyst component (2.1): metal of the catalyst component (22) is in the range from 100: 1 to 100: 10,000, preferably from 100: 10 to 100: 6000. The process according to the invention is characterized in that the catalyst system (KS) is used in the form of an intimate mixture (GE) of the catalyst system (KS) and a small particle diameter of 0.1 to 6.0 mm, preferably 0.1 to 1.0 mm having, not softening ethylene polymer (AEP) at the chosen polymerization, wherein the particles of the mixture (GE) with a solid at 30 ⁰ C, is liquid at the chosen polymerization temperature, saturated hydrocarbon wax (WA) are covered, such that the weight ratios are given as

: 10 to 1: 1000, preferably

: 25 to 1:50;

: 0.01 to 1: 1000, preferably

: 23 to I: 10; as

: 0.001 to 1:!, Preferably

: 0.1 to 1: 0.3.

(KS): (ÄP) of

from
(KS) :( WA) from

from
(ÄP) :( WA) from

from

Although it was already known, catalysts of the Ziegler type with fixed at 30 ° C, at the selected Polymerization temperature liquid saturated hydrocarbon waxes to coat on this Way to facilitate the handling of the catalytic converters and to reduce their fire hazard. On Due to this prior art, however, it could not be foreseen that it would also be known gas phase polymerization of ethylene with the help of Ziegler catalysts with the help of such Waxes would manage the particle size distribution of the polyethylenes obtained in the manner indicated to improve.

Apart from the special feature according to the invention

lu hen, the procedure can be carried out according to the relevant customary

Procedures and with the relevant customary Devices are carried out so that

in this respect, special explanations are unnecessary. It should only be mentioned that the procedure is nonetheless for the

is continuous and discontinuous polymerization suitable is

The following can be said in detail about the catalyst system (KS):

(1) The relevant customary suitable types are, for example, as carrier materials (1) described in the German Offenlegungsschriften 19 09 984 and 19 24648 as well as the interpreted Documentation of Belgian patent 7 05 220.

As it has been shown is particularly suitable a carrier material which has been obtained of the general through a 1 to 100, preferably 2 to 50 hours lasting hot-holding at a temperature of 150 to 600, preferably from 250 to 400 ⁰ C, of a fabric formula

^J0 (Me '%, · (Me>")" - (OH) ₀ - (CO ₃ ), · (H ₂ O),

where stand

Me "for a bivalent state

Metal or transition metal;
Me " ¹ for one in a trivalent state

Metal or transition metal;
m is an integer from 1 to 10, preferably

from 2 to 8, and especially 6;
π for an integer from 2 to 5, preferably

from 2 to 4, and especially 2;
ο for a whole number from 2 to 24, preferably

from 8 to 18, and especially 16;
ρ for an integer from 1 to 3, preferably

from 1 to 2, and especially 1;
q is an integer from 0 to 10, preferably

from 2 to 6, and especially 4;

with the proviso that the relationship holds

2 π + 3 / π = σ + 2 ρ = an integer from 8 to 26, preferably from 16 to 26, and especially 18.

Such a carrier material is obtained by adding a substance with the general formula given holds at the specified temperature for the specified time This can be done e.g. by simply keeping the affected substance hot in a heating furnace, as is the case with drying inorganic, Compounds containing water of crystallization are common.

The desired particle size can be achieved in a simple manner, e.g. B. by grinding can be adjusted. - In the given context, suitable metals or transition metals (Me ¹¹ ) present in a divalent state are z. B. beryllium, magnesium, calcium, strontium, bari-

b5 um, manganese, iron, cobalt, nickel, palladium, platinum, Copper, zinc, cadmium and mercury. Of these, magnesium, manganese, cobalt, Nickel, copper, zinc and cadmium; of this in turn

to be avoided are magnesium, manganese, cobalt, nickel, copper and zinc. The metals or transition metals (Me ") can be present as individual individuals or as mixtures of two or more individual individuals. In the given context, suitable metals or transition metals (Me ¹ ") present in a trivalent state are, for example, chromium, molybdenum, tungsten, iron , Ruthenium, osmium, rhenium, iridium, aluminum and gallium. Of these, chromium, molybdenum, tungsten, iron and aluminum are particularly suitable; Of these, in turn, preference is given to chrome and aluminum. The metals or transition metals (Me " ¹ ) can be present as individual individuals or as mixtures of two or more individual individuals. The substances with the general formula given are readily available . Transition metals are dissolved together in water in the form of water-soluble salts, such as chlorides, sulfates or preferably nitrates, in a proportion that corresponds to the desired composition of the substance and its stoichiometry obeys the general formula given 0.5 to 5, preferably 1.0 to 4, molar of metal or transition metal ions It is heated to a temperature of 50 to 100, preferably 60 to 90 ° C. and within 0.5 to 120, preferably from 1 to 60 minutes with an equivalent amount or preferably a slight excess of one to 50 to 100, preferably from 60 to 90 ° C heated 1 to 5, preferably L5 to 4 molar aqueous solution of an alkali metal carbonate, in particular sodium bicarbonate, combined. o, based on the theoretical amount of bicarbonate after the addition of the alkali bicarbonate solution, the mixture is advantageously stirred for about 10 to 30, preferably 15 to 20 minutes, then the precipitate formed is filtered off, washed with water and excess water is removed by suction obtained the substances of the type in question in almost quantitative yields.

(2) The actual catalyst (2) and also the catalyst components (2.1) and (22) can be referred to as the relevant conventional ones.

(2.1) Suitable catalyst components of this type are z. E.g .: TiQU ZrCl ₄ , VCl ₄ , VOCl ₃ , TiCl ₃ (OC ₄ H ₉ ) and TiCIj (OCjHs) J. Which are particularly well suited TiCl _4, VCl ₄ and VOCI _3; Of these, in turn, TiCl ₄ is preferred. The catalyst components (2.1) can be present as individual individuals or as mixtures of two or more individual individuals.

(2.2) Suitable catalyst components of this type are, for example: Mg (C ₄ H ₉ J ₂ , Al (C ₂ Hs) ₃ , Al (C ₃ H ₇ J ₃ , Al (C ₄ He) ₃ , Al (C ₈ H ₁ Z) ₃ , Al (C ₁₂ H ₂ S) ₃ , Al (C ₂ Hs) ₂ Cl, Al (C ₂ H ₅ WOCiHs) and Zn (C ₂ Hs) _2. Of these, pt are particularly suitable Al (C ₂ Hs ) ₃ , AKCsH;) !, Al (C ₄ Hs) ₃ , Al (C ₈ Hj ₇ H AKC ₁₂ H ₂ S) ₃ , Al (C ₂ Hs) ₂ Cl and Zn (C ₂ Hs) ₂ ; of these in turn preferred are the aluminum compounds. the catalyst components (22) can exist as individual compounds or as mixtures of two or me ^u r individual compounds.

The application of the catalyst (2) to the

Carrier material (1) can take place in the relevant customary manner. One method is e.g. B. in the fact that ma.i first brings the support material into contact with the catalyst component (2.1) and then into contact with the catalyst component (22). In detail you can expediently z. B. proceed so that msn the support material for several hours in the - boiling catalyst component (2.1) or a boiling solution of this - under normal conditions

ίο leaves the catalyst component, then washed it well with an inert solvent and then dried, for example in a vacuum. The intermediate product obtainable in this way can then easily be combined with the catalyst component (2.2) - for example present in a solution. - But there is also the possibility of first applying the catalyst component (22) and then the catalyst component (2.1) to the support material (1); it is also possible in special cases, the catalyst components (2.1) and

(22) to be applied to the carrier material at the same time.

The catalyst system (KS) discussed above is used according to the invention in the form of a Mixture (GE) from the catalyst system (KS) and a certain, small-scale ethylene polymer

(ÄP), the particles of the mixture (GE) with a certain wax (WA) are coated in a certain way. - Suitable in the given context Ethylene polymers do not have to, but should appropriately, be of the same type as the polyethylene produced in the process. - Grow with that required thermal property (melting range) are well known and commercially available, so that Insofar as it does not need to be discussed in more detail, it is only necessary to mention that the waxes are as far as possible Should be "clean," d. H. contain no ingredients - should poison the catalyst in question

can. The coating of the particles in the mixture from the catalyst system and the ethylene polymer with the wax can be done in a simple manner,

z. B. by putting the required amount of wax in one Mixing apparatus heated to just above the melting point of the wax, add the mixture, mix for as long as until the paraffin is absorbed practically homogeneously and then cools down. You can do all three just as well Heat the components together while mixing them above the melting point of the wax and then how proceed as above.

It should be pointed out at this point that when working with the catalyst components (2.1) and (22), the catalyst (2) and the catalyst system (KS), due to the sensitivity of these substances, the usual precautionary measures must of course be taken, ie in particular under Exclusion of water (moisture) and oxygen (air) has to work.

In the course of developing the present invention has also been shown that it can be desirable if the ethylene to be polymerized in the Mixture with hydrogen begins in such a way that up to 100 parts by volume of the ethylene to be polymerized 150 parts by volume of hydrogen are omitted. - This measure will expediently be taken if you want to obtain a polyethylene which has the smallest possible fraction of particles, their

Particle diameter is more than 4 mm (so-called "oversize grain"). The function of hydrogen directed in this way grows with its concentration as well as with increasing Polymerization temperature.

example 1

A substance of the formula is assumed
(Mg '% · (AIW) ₂ · (OH) ₁₆ · (CO ₃ ), · (H ₂ O) ₄

300 g of this substance are ^{distributed over an area of 400 cm 2} in a drying oven and kept at a temperature of 290 ^° C. for 15 hours. This results in a carrier material (1) which is brought to a partial diameter of about 0.005 to 0.1 mm by grinding. In a conventional extraction apparatus, which has a flask, an extraction part with a glass frit located above the flask, a stirrer located in the extraction part and a reflux condenser located above the extraction part, 200 g of the carrier material are poured into the part intended for extraction (per se). _{1.5 liters of TiCl 4} are added to the flask. The TiCl _{4 is} then heated to the boil and kept boiling for a further 7 hours; as long as the carrier material is in contact with TiCl ₄ . The carrier material loaded with TiCl ₄ is then washed with n-heptane and dried in vacuo at room temperature. The result is an intermediate product of the catalyst system in which the weight ratio of support material: TiCl ₄ - based on Ti - is about 100: 0.63. 125 parts by weight of this intermediate product are then mixed homogeneously _{with 142 parts by weight of Al (C 2} Hs) _{3 in a stirred vessel at room temperature.} This results in a catalyst system (KS) in which the atomic ratio Ti: Al is about 100: 2000.

In a heatable mixer (8 I capacity) are introduced: 55 g of the catalyst system (KS), 1200 g of a finely divided, a particle diameter of 0.5 to 1 mm comprising polyethylene and 4Og pure (softening range 25 to 36 ⁰ C!)! Paraffin (DAB 6; melting range 69 to 73 ° C). With constant mixing, the mixture is heated to 80 ^° C. within 30 minutes, this temperature is maintained for 5 minutes and then cooled to room temperature.

The polymerization itself is carried out continuously in a stirred reactor with a capacity of 200 l has and in the continuously stationary state as a bed 45 kg of dry, small-sized polyethylene with contains a particle diameter of 0.1 to 6 mm. The ethylene pressure in the reactor is constant at 35 atmospheres Temperature kept constant at 95 ° C. The hourly in The amount of paraffin-coated mixture charged into the reactor is 0.4 g. In this way are per hour 4 kg of a small-scale polyethylene with a particle diameter of 0.1 to 6 mm obtain. The particle size distribution of the polyethylene is given in Table I.

Comparative experiment

The procedure is exactly as in Example 1, with the only exception that it is carried out without paraffin. The particle size distribution of the polyethylene obtained is also given in Table I:

Table I.

> Sieve fraction Example I. Attempted comparison |% By weight] [% By weight | ^ - ^ ΠΊΓΓι O £
O, l> 3 to 2 mm 17.0 14.2 2 to 1 mm 10.4 14.4 1 to 0.75 mm 4.7 6.0 0.75 to 0.5 mm 3.0 5.2 0.5 to 0.4 mm 0.3 3.9 0.4 to 0.3 mm 0.2 10.1 '0.3 to 0.2 mm 0.1 16.0 0.2 to 0.1 mm - 18.2 <0.1 mm - 3.4

Examples 2-4

The procedure is exactly the same as in Example 1, with the three exceptions: it is with alternating mixtures worked from ethylene and hydrogen (see. Table II), the total pressure being held at 35 atmospheres in each case will; it is polymerized at a temperature of 110 ° C; 0.7 g per hour are fed into the reactor of the mixture coated with paraffin. The results are shown in Table II.

Table II Example no.

Volume parts H ₂
per 100 parts by volume
Ethylene

Sieve fraction
> 4 mm

[% By weight]

1.5
11.0
33.0

72
33
17th

Claims (1)

Patent claims: 1. Process for the production of polyethylene by polymerizing ethylene at temperatures of 50 to 130 ⁰ C and pressures of 10 to 200 atm in a moving bed of dry, small-particle polyethylene with a particle diameter of 0.1 to 6.0 mm by means of a catalyst system ( KS) from ίο